Fly ash is a byproduct from the burning of coal in coal fired power stations and is produced in abundance. Fly ash is a very fine powder, easily airborne, and typically contains minute amounts of heavy metals such as cadmium, chromium, zinc and lead that make disposal problematic. In trying to minimise the environmental impact of fly ash, various uses of fly ash have been contemplated to both aid in fly ash disposal and to obtain some economic return. However difficulties have been encountered in manufacturing fly ash containing articles such as tiles or the like that can be manufactured on industrial scale, are cost competitive with existing products that they replace, are of a consistent quality and perform adequately over a range of structural and technical properties.